Oh boy, lots of catching up to do!
doglover had a few questions so thought I'd pop in and try to help......oh yeah and "officially" welcome her!
First, I LOVE your "greenmen"!
I've used both E-6000 and Thinset to "glue" mosaics to cement and both have worked well. Personally, I think E-6000 is easier to use but it's a little stinky!
FYI, Walmart has the cheapest price on E-6000 I've found,
$1.00 less a tube than Michael's! Thinset works better for 'some' things, especially if you're applying glass or tiles with different thicknesses. I've only been working with mosaics for a year so I'm still learning about all the different techniques.
You asked about "painting" cement. I've done a lot of research and even though I don't have years of hands-on experience this is what I've read. Most any paint will
work but 'some' are better than others. I've had pretty good luck just using the cheap acrylic paints but like any painted surface you need to apply a sealer (more on that in a minute). Sharon's right, the color won't last "forever" but after two years most things I've done are still holding up well. Any latex house paint works well too. I haven't gone the extra step yet to purchase "outdoor" acrylic paints or "patio paints" but supposedly they'll hold their color longer. They do cost a little more and I've been too cheap to pay the extra price!
Stains for concrete are available and provide a longer lasting option because they penetrate the concrete versus using paint which just coats the surface. Unfortunately the stains readily available (Lowes/Home Depot) don't offer much for color options. In order to achieve some of the really unique looks I've seen with stained concrete it's usually necessary to order these special stains. They're not cheap and from reports I've seen, a little tricky to use.
Sealers - the most important thing to remember is to buy a product which
specifically states it's a "
penetrating" sealer. I know people who have used polyurethane or marine varnish but again, just like the paint, they "coat" the concrete versus penetrating it. Another of my reasons for avoiding these products is because they have a tendency to 'yellow' with exposure to the sun. The only problem I have with most penetrating sealers is they usually have a glossy or semi-glossy finish and most of the time I prefer a 'matte' finish. I solved this problem by using three coats of a penetrating sealer and then a quick finish coat with clear matte spray paint.
Whew!
Hope that information helps you!